Dispersion hardened high strength brass alloy



United States Patent 3,544,313 DISPERSION HARDENED HIGH STRENGTH BRASS ALLOY Akira Sadoshima, 6 3-chome, Andojibashi-dori, Minamiku, Osaka, Japan, and Saburo Yoshikawa, 459 Miwa, Sakurai-shi, Nara-ken, Japan No Drawing. Filed Jan. 23, 1968, Ser. No. 699,784 Int. Cl. C22c 9/04 US. Cl. 75157.5 4 Claims ABSTRACT OF THE DISCLOSURE An intermetallic compound or compounds formed by aluminum on one part and titanium or zirconium of Group IVa or chromium or molybdenum of Group VIa of the periodic table on the other part, is or are added to a wrought high strength brass alloy having a structure of 04-1-5 solid solution or a B solid solution containing no iron; and is or are dispersed therein so as to strengthen the matrix of said brass alloy. Said brass alloy so produced, which is to be used for constituent parts of various machinery, has a greater strength, a greater resistance to wear and a better refractory property, and can be produced at a lower cost of production.

In order to obtain the greater strength of a high 3,544,313 Patented Dec. 1, 1970 Example 1 shows the chemical compositions by Weight of ASTM B138 Copper Alloy No. 670 and of some alloys prepared in accordance with the present invention.

EXAMPLE I ASTM B 138 Alloy Chemical composition, Copper alloy weight percent N0 67 A B C D Copper 63. 0-68. 0 62. 4 64. 6 58. 3 63.5 Aluminum. 3. 0-6. 0 4. 1 4. 8 3. 3 3. 9 Manganese- 2. 5-5. 0 3. 0 2. 9 l. 6 1. 2 Iron 2. 0-4. 0 nil m'l nil m'l Tin 0. 5 1 nil nil 0. 01 nil Lead 0. 2 1 0. 02 0. 3 nil nil Nickel 0.6 0 6 0. 3 0. 4

1 Maximum. 2 Balance.

Table 1 shows the various comparisons of the average mechanical properties of the alloys mentioned in Example I.

TABLE I ASTM B 138 Alloy Copper Alloy Mechanical properties as extruded N o. 670 A B O D Tensile strength p.s.1 92, 000 113 000 110, 000 121, 000 104, 000 Yield strength p.s.i 56, 000 78, 000 75, 000 80, 000 72, 000 Percent elongation 2' 21 14 18 10 15 strength brass alloy, it is found out that the alloy is prepared by the following method: From 0.05% to 10% by weight of 'an intermetallic compound or compounds, that is, one or more of titanium aluminide, zirconium aluminide, chromium aluminide or molybdenum aluminide is or are added to a a-I-B solid solution or a ,8 solid solution base alloy consisting by weight of from 54% to 68% copper, from 3% to 7% aluminum, from 2.0% to 5.0% manganese, max. 1% nickel, up to 0.02% tin, max. 0.5% lead, zinc constituing the remaining part, and containing no iron.

Titanium, zirconium, chromium or molybdenum produces an aluminide with the aluminum in the base alloy and form with it a minute intermetallic compound which disperses in the matrix of the base alloy and checks the movability of dislocation 1, the plastic deformation, and which strengthens the strength of the high strength brass alloy.

An addition of each intermetallic compound among a group of titanium aluminide, zirconium aluminide, chromium aluminide and molybdenum aluminide may be performed either in a form of each intermetallic compound or in a form of a single substance of each element or in a form of mother alloy when the high strength brass alloy of the base is melted. In the latter two cases, such a single substance or mother alloy forms an intermetallic compound with the aluminum in the base alloy. In all the cases, the intermetallic compound will disperse in the matrix of the base alloy after the base alloy has been solidified.

The above table shows clearly that the dispersion of intermetallic compounds improves the mechanical properties of the alloys to a marked degree.

The conventional high strength brass alloy as, for example, ASTM B 138 Copper Alloy No. 670, ASTM B 147 8B, or the alloy described in the specification of US. Patent 3,097,093, has as its main constituents copper, aluminum, manganese, iron and zinc, and also contains minute quantities of tin and lead. In our studies of improving a resistance to wear of the high strength brass alloy, however, it has been found out that the presence of iron has an ill effect on the alloy. There is no iron, therefore, in the base alloy of the high strength brass alloy developed in accordance with the present invention. An increase in the strength of the high strength brass alloy by means of iron can be sufficiently made up for by an addition of an intermetallic compound or com pounds prepared in accordance with the present invention.

Table II shows comparative wear test results between ASTM B 138 Copper Alloy No. 670 and one of the alloys prepared in accordance with the present invention. It is clear that the alloy containing no iron has a greater resistance to wear.

TABLE II.WEAR TEST (AVERAGE) Alloy: Amount of Wear, g./ cm. km.

ASTM B 138 Copper Alloy No. 670 as extruded 0.26 Alloy A as extruded 0.09

Load 40 kg./cm. sliding speed 1 m./sec.

As a dispersed intermetallic compound doesnot dis-..

solve in the matrix at a high temperature, the alloy does not decrease much in its strength even at the high temperature.

Table III shows the hardness of the alloy after it has been heated with a high temperature.

TABLE III.ALLOY A AS EXTRUDED Reduce hardness of Diamond pyramid hardness at high Temperature After having been heated, the alloy was cooled at the room temperature and measured.

In the specification of US. Patent 3,097,093 (1st colum, line 33 and the following), it is described to the eifect that the presence of lead decreases the impact strength of an alloy, and consequently the content of lead is limited up to 0.2%. In our studies, however, lead can be added up to 0.5% to the alloy in accordance with our invention without an appreciable ill effect. On the contrary, such a presence of lead increases the machinability.

Example 2 and Table IV show the comparisons of the alloy containing lead with the alloy containing no lead, both alloys being prepared in accordance with our invention. Table IV shows clearly that the addition of lead does not decrease the impact strength of the alloy.

EXAMPLE II Chemical composition, weight percent Alloy E Alloy F 64. 7 64. 4. 2 4. 1 2. 0 1. 9 0. 3 0. 3 0. 3 0. 3 0. 1 0. 1 nil 0. 4 0) Impact strength Charpy V-notion,

kgm./cm. at room temperature 4.7 4.8

Alloy 'E Alloy F We claim as our invention:

1. A a+p solid solution dispersion hardened high strength brass alloy consisting essentially of, by weight, from 54% to 68% copper, from 3.0% to 7.0% aluminum, from 2.0% to 5.0% manganese, from 0 to 1% nickel, from 0 to 0.02% tin, from 0 to 0.5% lead, and from 0.05% to 10% of an intermetallic compound se lected from titanium aluminide, zirconium aluminide, chromium aluminide, molybdenumaluminide and balance zinc, said alloy being characterized in that it has high strength and has excellent resistance to wear, and good refractory properties, and that it contains no iron at all.

2. The oc-l-fi solid solution dispersion hardened strength brass alloy of claim 1 wherein said intermetallic compound is a plurality of intermetallic compounds.

3. A ,8 solid solution dispersion hardened high strength brass alloy consisting essentially of, by weight, from 54% to 68% copper, from 3.0% to 7.0% aluminum, from 2.0% to 5.0% manganese, from 0 to 1.0% nickel, from 0 to 0.02% tin, from 0 to 0.5% lead, and from 0.05% to 10% of an intermetallic compound selected from titanium aluminide, zironconium aluminide, chromium aluminide, molybdenum aluminide and balance zinc, said 'alloy being characterized in that it has high strength and has excellent resistance to wear, and good refractory properties, and that it contains no iron at all.

4. The 13 solid solution dispersion hardened high strength brass alloy of claim 3 wherein said intermetallic compound is a plurality of intermetallic compounds.

References Cited UNITED STATES PATENTS 1,869,554 8/1932 Ellis --157.5 3,097,093 7/1963 FOX et al 751 57.5 X 3,297,497 l/ 1967 Eichelmon et al. 75162 X OTHER REFERENCES Campbells List of Alloys, ASTM, 1930, p. 11.

CHARLES N. LOVELL, Primary Examiner US. Cl. XR. 1 

